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FMComms5 Configuration Options

RF Ports

By default the FMComms5 is configured with the Minicircuits TCM1-63AX+ baluns on the Rx1A, Rx2A, Rx1C, Tx1A, Tx2A, and Tx1B channels. This wideband balun allows for tuning across the entire 6GHz range of the AD9361, although performance may be compromised at some frequencies. The Rx1B and Rx2B channels use the Johanson 2450BL15B050E balun, which is optimized for 2.4GHz. Other balun options that are footprint compatible with this part, but optimized for other frequency bands are:

Manufacturer Frequency (MHz) Balun number Impedance AC coupling
TDK 350 HHM1591D1 50/100 100pF
TDK 900 HHM1564A4 50/200 100pF
Johanson 1450 1450BL15A200E 50/200 20pF
Johanson 1600 1600BL15B050E 50/50 20pf
Anaren 1631 BD1631J50100A00 50/100 18pF
Johanson 2450 2450BL15B200E 50/200 9pF
Johanson 2450 2450BL15B050E 50/50 18pF
Hitachi 3000 ESLT-S370KBI 50/50 10pF
Johanson 5400 5400BL15K050E 50/50 10pF
Hitachi 5000 ESLT_S540E 50/50 10pF

Additionally the Rx1B and Rx2B paths include the ADL5521 LNA and a 2.4GHz RF SAW filter. The Tx1A and Tx2A paths include the option of using capacitors to switch in the same SAW filter as well as the ADL5602 RF amplifier. These external amplifiers and filters can be used to better prototype final the final system design.

External Clock

By default the FMComms5 uses a Rakon 40MHz RXO3225M as the reference clock. This is driven into the ADCLK846, which distributes the clock to the two AD9361s, the ADF5355, as well as back to the FMC connector. It is important that the PCB trace lengths to the two AD9361s be equally matched.

This on board reference can be bypassed by placing C301 and removing R360. In this configuration an external reference clock can be injected into J301. The level of the external reference should be ensured to not exceed the ADCLK846 input conditions, and it will still be used to distribute the reference clock to the two AD9361s.

External PLL

The FMComms5 comes with the layout provisions to accept the ADF5355 when it is released in 4Q14. In the interim, an external LO signal can be injected into J302. This LO will be distributed to the two AD9361s by the Inphi 13617. Similar to the reference clock distribution, length matching is very critical for the external LO routes.

When the ADF5355 is available, it can be inserted into the design by soldering down the device, placing C331 and C332 and removing C390. In this configuration the RFOutA port of the ADF5355 port is in circuit, which allows for external LO generation up to 7GHz (divided to 3.5GHz in the AD9361). To generate an LO signal up to 8GHz (4GHz after the divide by 2 in the AD9361), the RFOutB node must be used. To select this net remove C331 and C332, and place C353 and C390.

R350 should be DNI for all configurations.

resources/eval/user-guides/ad-fmcomms5-ebz/hardware/configuration_options.1417547524.txt.gz · Last modified: 02 Dec 2014 20:12 by Robin Getz